1. Field of the Invention
The present invention concerns a device for producing columns of material in the ground, in particular under water, for example on the sea floor.
2. Description of the Related Art
A device with a deep vibrator for producing columns of material in the ground is known for example from DE 197 07 687 C1.
Further, in DE 198 14 021 A1 a device for producing columns of material in the ground is described, which includes a deep vibrator and an extension pipe connected to the deep vibrator, which can be acted upon with pressure. Connected to the upper end of the extension pipe is a lock or charge chamber, with a first closure mechanism provided between the charge chamber and the extension pipe, and a second closure mechanism on the side opposite the extension pipe. In the known device the material to be introduced into the ground, for example concrete or gravel, enters via the second closure mechanism into the first charge chamber, from where, with closed second closure mechanism and open first closure mechanism, it enters into the extension pipe which is under pressure. The pressure in the extension pipe serves to overcome the water pressure at the tip of the deep vibrator and thereby to extrude material at the vibrator tip. This type of deep vibrator is referred to as a charge chamber vibrator.
The present invention is concerned with the task of providing a device for producing columns of material in the ground of bodies of water, in particular under bodies of water of great depth.
This task is solved by a device having the characterizing features of claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.
The inventive device includes first and second material tanks, which are connected with each other, and a deep vibrator for introduction of material into the ground, which is connected with the second material tank. A first closure means is provided between the first and second material tanks. A first supply line is connected to the first material tank for supply of material and a second supply line or as the case may be a pressure equalizing line is connected to the first material tank for equalizing pressure in the first material tank.
During the introduction of material columns into the ground of bodies of water the deep vibrator and the first and second material tanks are under water, they are thus under a pressure which is greater than the atmospheric pressure at the water surface. The first supply line serves for conveying the material to be introduced into the ground from a reservoir at the surface of the water, for example from a ship, under pressure into the first material tank. The second line or hose, which preferably likewise leads up to the surface of the water, enables a pressure equalization between the pressure at the water surface and the first material tank. The pressure in the first supply line for supplying the material, for example gravel or concrete, must thus be selected to be sufficiently high in order that the material is conveyed with sufficient flow velocity at atmospheric pressure. This pressure conventionally is less than 7.5 bar. The ambient pressure in the water in the environment of the first material tank is at the same time substantial.
The pressure equalization in the first material tank by means of the second line has as a consequence that for the first supply line for supplying material to the first material tank, which is now at atmospheric pressure, a hose can be employed which is designed merely for the same pressures used for conveying of material on land. There is no need for incurring the cost of expensive special hoses, which are designed for high pressure.
Floats are preferably provided in the area of the end of the second supply line opposite to the first material tank in order to keep that end of the line on the surface of the water.
In order to prevent the high pressure, which exists in the second material tank during the operation thereof as necessary for introduction of the material to the floor, from being lost via the pressure equalizing line during opening of the first closure means, at least one additional closure means is preferably provided, which is located between the first and second supply lines and at least one area of the first material tank.
In a further preferred embodiment second and third closure means are provided between the first supply line and the first material tank and between the second supply line and the first material tank, which are respectively opened when material is supplied via the first supply line to the first material tank. When the second and third closure means are closed, the first closure means between the first and second material tanks can be opened, whereupon the material can be supplied to the deep vibrator conventionally via a pipe extending into the depth. A compressor is preferably connected to the second material tank in order to build up pressure in the second material tank which is greater than the water pressure at the tip of the deep vibrator, whereby the material can be extruded at the tip of the deep vibrator. The closing of the second and third closure means during opening of the first closure means brings about that the pressure in the second material tank remains establishedxe2x80x94a pressure equalization occurs only within the limited volume of the first chamberxe2x80x94so that no dirt out of the ground, in which the tip of the deep vibrator is located, is sucked in.
According to a further embodiment of the invention it is proposed that the compressor is also connected to the first material tank, whereby the pressure can remain established in the first material tank following the closing of the first and second closure means, which pressure corresponds to the pressure in the second material tank. The seating of the first closure means between the first and second material tanks, and which may be for example be a slide valve, is thereby unburdened during the opening of the first closure means. This is in particular useful and sometimes necessary, when work has been carried out at great depth and a corresponding great pressure is necessary in the second material tank for extrusion of the material.
In a further embodiment it is envisioned that the first material tank includes a first chamber, in which the first and second supply lines communicate, and a second chamber, wherein a further closure means is provided between the first and second chambers and wherein the first closure means is provided between the second chamber of the first material tank and the second material tank. The additional closure means is thus between the first and second supply lines and the second chamber of the first material tank. With this embodiment it becomes possible to omit the closure means between each of the supply lines and the first material tank. The first chamber of the first material tank is in this embodiment continuously under atmospheric pressure, which is established by the pressure equalization line. The second chamber of the first material tank, which is separated from the first chamber by the further closure means, establishes the pressure charge chamber, into which during operation material can be introduced out of the first chamber when the additional closure means is opened and the first closure means is closed. Following the closing of the additional closure means the material out of the second chamber passes into the second material tank, via which it, conventionally via a conveyance pipe, is brought to the tip of the deep vibrator and from there into the ground.
With this embodiment the amount of material, which is respectively all at once brought to the second material tank and from there extruded to the ground, is determined by the volume of the second chamber, which upon opening of the further charge chamber is completely filled, when the volume of the material present in the first chamber is greater than the maximal volume of the second chamber. Thereby in simple manner the amount of the material already introduced into the ground can be determined.
The first closure means between the first and second material tank and/or the additional closure means between the first and second chamber of the first material tank are preferably provided with slide valves or as the case may be have a slideable closure element.
In order not to overload the bearing surfaces of these slide valves or, as the case may be, slideable closure elements, during opening due to the pressure differential between the first and second material tank and/or between the first and second chambers of the first material tank, in accordance with one embodiment of the invention a first pressure equalizing element is provided between the first and second material tank and second pressure equalizing element is provided between the first and second chamber of the first material tank. The first pressure equalizing element is designed in order, prior to the opening of the first closure means, to bring about a pressure equalization between the second material tank and the first material tank or as the case may be the second chamber of the first material tank, and the second pressure equalizing element is designed in order, prior to opening of the additional closure means between the first and second chamber of the first material tank, to bring about a pressure equalization between these two chambers.
The subject of the present invention is further a process for producing columns of material in the ground according to Claims 16 through 20.